/*
 * @lc app=leetcode.cn id=1 lang=javascript
 *
 * [1] 两数之和
 *
 * https://leetcode-cn.com/problems/two-sum/description/
 *
 * algorithms
 * Easy (49.40%)
 * Likes:    9158
 * Dislikes: 0
 * Total Accepted:    1.4M
 * Total Submissions: 2.8M
 * Testcase Example:  '[2,7,11,15]\n9'
 *
 * 给定一个整数数组 nums 和一个目标值 target，请你在该数组中找出和为目标值的那 两个 整数，并返回他们的数组下标。
 *
 * 你可以假设每种输入只会对应一个答案。但是，数组中同一个元素不能使用两遍。
 *
 *
 *
 * 示例:
 *
 * 给定 nums = [2, 7, 11, 15], target = 9
 *
 * 因为 nums[0] + nums[1] = 2 + 7 = 9
 * 所以返回 [0, 1]
 *
 *
 */

// @lc code=start
/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function (nums, target) {
  let map = new Map();
  while (nums.length > 0) {
    let index = nums.length - 1;
    let current = nums.pop();
    let diff = target - current;
    if (map.has(diff)) return [index, map.get(diff)];
    map.set(current, index);
  }
};
// @lc code=end
